<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>检查⼀个数是否为整数</title>
</head>
<body>
    <script>
        var arr = prompt('请输入一个数，判断它是否为整数');
        arr = Number(arr);
        if(arr % 1 === 0){
            alert('是整数');
        }else{
            alert('不是整数');
        }
    </script>
</body>
</html>